Gone through 3 winters with mine and I love it. Just a thought on the return air, I place a 20x20 Ultra Filtrete 1900 (or even now a 2200) in the line and also have an Aprilaire prefilter. I love my air super clean. The use of a 14" line will keep the noise down, I hardly hear mine. Your ducting is much more professional than mine and I love the photo.
Gotchas, keep the lower exhaust cleaned out. Ash accumulates there quickly and reduces air flow so use low ash coal. I put a tee piece there in the exhaust at the stove exit point and the 6" end cap is not even sealed or even screwed in place. I simply remove it and vacuum it out (baro covered up with a damp facecloth and powervent on full with the stove still on). Small leaks? sure, but I keep an eye on my Dwyer and that controls my life. I fact I don't even seal the whole exhaust stack (duck - incoming) but clean it out monthly and leak blower suck out the powervent (thx sting) with the stove still on low. Don't try that at home, it's for idiots only and it is within three feet of a 5' door that is open for this operation.
The design is super efficient as a result of the tubes and I like to run a brush over them (quickly so you don't wreck the brush - 10 second operation that's 5 secs per side every few days) every few days to remove ash from the top this helps heat transfer (I think). Keep those fins clean on the combustion squirrel cage air fan as that reduces airflow too. I use rice but am thinking of buck - anybody any thoughts? So would I buy another - in a heartbeat. It has already paid for itself in saved HO - all gravy from here on out and I control the upstairs rooms to within a degree or two without plumbed cold air return but that takes practice and your mileage may vary - thx Dave. All this and I did not buy a Peruvian copper mine (incoming again).